Switch



y 1950 c. F. exssow 2,506,208

SWITCH Filed Feb. 4, 1947 I )1 z'entor Clarence F. Gibson WW EM Patented May 2, 1950 UNITED STATES PATENT OFFICE SWITCH Clarence F. Gibson, Benicia, Calif. Application February 4, 1947, Serial No. 726,294

3 Claims.

This invention relates to new and useful improvements and structural refinements in switches, more specifically, electric switches, and the principal object of the invention is to provide a device of the character herein described, such as may be conveniently and effectively employed in association with internal combustion engines on automobiles, or the like, for the purpose of automatically discontinuing the supply of electric current to the ignition system when, for some reason, the oil pressure falls below normal.

A further object of the invention is to provide a switch which may be used in such manner as not to interfere with the normal delivery of electric current to the ignition system before the oil pressure is built up, while the engine is being started.

Another object of the invention is to provide a switch which is simple in construction, dependable in operation and which, in view of its function, will prevent considerable damage to the engine, such as frequently results when the latter is operated with low or without any oil pressure.

An additional object of the invention is to provide a switch which may be easily and conveniently adjusted, so as to open the ignition circuit as soon as the oiling system falls to a predetermined pressure. It will be apparent that in this manner, the invention will also eliminat undue loss of current from the storage battery, which frequently occurs when the operator of the engine forgets to turn off the conventional ignition Switch.

A still further object of the invention is to provide a switch which may be readily installed in position, which may be easily disassembled for purposes of inspection or repair, and which will readily lend itself to economical manufacture. With the above more important objects in view, and such other objects as may become apparent as this specification proceeds, the invention consists essentially of the arrangement and. construction of parts as illustrated in the accompanying drawings, in which:

Figure 1 is a cross-sectional view of the invention, taken substantially in the plane of the line l-i of Figure 2.

Figure 2 is a top plan view of the device shown in Figure 1, and

Figure 3 is a wiring diagram, showing the invention in use.

' Like characters of reference are used to designate like parts in the specification and throughout the several views.

Referring now to the accompanying drawings in detail, the invention consists of a switch designated generallyby the reference numeral Hi, the same embodying .in its. construction a substantially cylindrical housing H, provided at the ends thereof with out-turned flanges l2 and I3.

It will be noted that the end of the housing adjacent the flange l3 isclosed as indicated at l5, while a removable cover I6 is secured to the flange l2 at the relatively opposite end of the housing by means of suitable screws l1.

A dome-shaped cap I8 is removably attached to the flan e H by a plurality of further screws l9, and a diaphragm 20 is interposed between the flange and the cap, as is best shown in Figure 1. It will be also observed that the cap it is provided with a screw-threaded boss 2|, the latter being adapted to receive an oil pressure line 22 which communicates with the oiling system of the engine with which the invention is used.

It will be seen from the foregoing that the interior of the cap 18 provides what may be referr'ed to as a fluid chamber 23 which is further defined by the diaphragm 20.

Similarly, the interior of the housing I l constitutes a mechanical chamber 24 which provides an enclosure for, inter alia, a cylindrical guide 25.

The guide 25 is formed integrally with the closed end I5 of the housing H, and said closed end is formed with an aperture 26 which communicates with the interior of the guide, as will be clearly apparent. In effect, the aperture 26 constitutes a continuation of the bore of the guide 25, the remaining end of the guide being closed as indicated at 21 and being formed with a further aperture 28.

A plunger 29 is slidably positioned in the aperture 28 and is screw-threaded at one end thereof (as at 30) into a dome shaped end piece 3 !V which, in turn, contacts the diaphragm 20. It will be noted that the end piece 3! is slidably disposed in the opening 26 and in the cylindrical guide 25, as will be clearly understood.

The inner end of the plunger 29 is provided with a disc 32, while the inner surface of the cover I6 is formed integrally with a tubular sleeve 33. An adjusting screw 34 is threaded into this sleeve through a suitable opening provided in the cover [6, and a compression spring 35 is interposed between the screw 34 and the disc 32. The sleeve 33 constitutes what may be referred to as a seat or guide for the spring 35, and the primary purpose of the spring is to urge the plunger 29 and the associated end piece 3! toward the diaphragm 20. The screw 34 is provided with a suitable lock nut 36, for obvious reasons.

A bell crank 31is pivoted as at 38 to a bracket 39 secured to the inner surface of the housing I I, one arm of the bell crank being disposed between the closed end 2! of the guide 25 and the disc 32 of the plunger 29. The remaining arm of the bell crank 3! carries a conductive member or por-, tion 40 which, in turn, is provided with a contact point 4|. A coactingcontact point 42 is mounted on an insulated conductor ring 43 secured to the guide 25, the point 42 being stationary, as will be clearly apparent.

The lateral wall of the housing H is provided with a pairof terminal posts 44 and 45, these, of course, being insulated with respect to the housing and simply assuming the form of suitable.

screws, insulating washers and nuts, substantially as shown in Figure 1. The post 45 is electrically connected by means of a wire 46 to the conductor ring 43, while a leaf spring 41, configurated substantially as shown, is secured to the terminal post 44. The free end portion ofthe spring v41 bears against the adjacent arm of the crank 31 and the spring thus performs a double function, namely, that of electrically connecting the post at -to-.-the contact 4! through themediumof conducti've member 48, and urging the other arm of the bell crank against the disc 32.

With particular reference-to the accompanying Figure 3, the terminal post 44 is connected by means of a conductor 48' to onepole 49 of a storage. battery 56,. the remaining pole oi the battery being grounded in the. conventional manner, as indicated at lit. The battery pole:4;9 is also connected by means of. a conductor 52. tonne contact 53 of atwo way ignition switch 54. The remaining contact. 55 of the switch 54 is connected against the diaphragm 20;. as has beenalready explained.

In such event,'the points. 4i and 42 will be separated and no current will be deliveredv through the open switch ill .from the battery 59 to'the distributor of the engine. However, the engine may be startedby simply manipulating the lever 59 so as to complete the circuit between the con- "tact 53 and the terminal 51, and as soon as oil pressure exists in the chamber 23,'the diaphragm '20- will force the plunger 29 against-the resiliency of the spring 35, thereby permitting the contacts '41, 42 to become engaged in a CiY-GUltnGiOSlHQlQOSl- 'tion, under the influence of the spring 41:. Cur rent will now pass through the switch Ill, and the arm 59 of the switch 5.4; may be set so as to establish electrical connection between the contact 55 and the terminal 51.

Thereupon, the ignition system oi the engine will be dependent for its supply or electricity en tirely upon the switch it and. in the, event that the oil pressure falls to normal, the resiliency of the spring 35 will overcome the resiliency oi the spring 6.! and the contact points ll, 42 will be automatically separated.

. It will be apparent that in this manner, the engine will be stopped as soon as the oil pressure drops below normal, this action being governed by the resiliency of the spring 35. This,;in turn, isgoverned by the setting of the screw 34 and the latter should, of course, be adjusted so that the points 4|, 42 are separated as soon as the oiling systemof the engine drops to apredetermin'ed pressure.

thereof "at this point is considered unnecessary.

" TWhile in the foregoing there has been shown and described the preferred embodiment of this invention it is to be understood that minor changes in the details of construction, combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as claimed.

What I claim as my invention is:

1. A pressure actuated switch comprising a housing having a bottom Wall, a cylindrical guide integrally formed with the bottom wall, an opening provided in the bottom wall communicating with said guide, a plate integrally formed with said guide having a central opening, a piston rod slidably received in the opening in said plate, a piston carried by said rod slidably received in said guide and the opening in said bottom wall, a stop disk fixed to said rod and disposed exteriorlyof said plate, a cap carried by said bottom wall, a diaphragm interposed between said cap and bottom wall for moving the piston and piston rod, resilient means normally urging the piston against the diaphragm, a contact point carried by the housing, a substantially L-shaped lever mounted in said housing for pivotal movement, a contact carried by the longer leg of said lever for engaging said fixed contact, and means acting on the longer leg of said lever for urging the contact thereontoward the fixed contact, the shorter leg of said lever-being normally clamped between said plate and said stopt'o space-said contacts.

2. A pressure actuated switch comprising a housing, a hollow support mounted'in said housing including an upper wall, fixedcontact mounted in said housing, a substantially L- shaped lever mounted in said housing for pivotal movement, acontact carried by the longer leg of said lover, a sliding member mounted in the support and including an abutment for clamping the shorter leg of saidlever against the upper wall to retain the contact carried by the lever spaced from the fixed contact, means urging the contact carried by said lever into circuit closing position with said fixed contact, and a diaphragm carried by the housing for moving the sliding member to urge the abutment from the shorter leg of said lever.

I 3. A pressure actuated switch comprising a housing, a support mounted in saidhousingincluding an upper wall, a fixed contact mounted in said housing, a substantially L-shaped lever mounted in said housing for pivotal movement, a contact carried by the longer leg of said lever, means for clamping the shorter leg of said lever against the upper wall and the contact carried by the lever spaced from the fixed contact, means urging the contact carried by saidlever into circuit closing position with said fixed contact, and means for releasing saidfirst mentioned means, said first mentioned means including a spring urged plunger having a stop adapted to bear against the shorter leg of said lever.

' CLARENCE F. GIBSON.

REFEEJENCES' CITED UNITED STATES; BA. I

Number Name Date 2,178,953 Chilton Nov. '7, 1939 2,223,689 Jennings Dec. 3, 1950 2,241,056 Chilton ...IMay 6, 1951. 2,428,096 Reavis J S,ept1.30, 1,957 

